The present invention relates to a process for selectively cutting an electrical conductive layer by irradiation with an energy beam.
Increasing the integration of elements in a semiconductor device, such as a dynamic random access memory, has made it desirable not to have to scrap an entire semiconductor chip just because of a failure of one element in the chip. Toward this end, "redundant" circuits have been developed. To salvage a chip found to have a faulty element in one cell, the redundant circuit is activated and the circuit which leads to the faulty cell is cut. Selective cutting of electrical conductive layers has been developed to meet this requirement in the production of random access memories (RAM's), read only memories (ROM's), and other devices.
It is well known in the art to selectively cut conductive layers by partial removal of the metallic layer with an etchant or by melting the metallic layer with an excess current. Recently, selective cutting by laser beams has come to attention in the art. Accurate, selective cutting of a layer can be realized, since scanning with a laser beam can be controlled accurately.
However, the smallest diameter that a laser beam can be practically made is about 3 .mu.m. On the other hand, in an integrated circuit with a high packing density, the width of aluminum wirings and the space between them may be no more than 1 .mu.m. Thus, the irradiated spot covers adjacent wirings.